The present invention relates to a wheeled dolly for converting a long-log trailer having a cantilevered reach into a short-log trailer having a reach extending rigidly between spaced-apart sets of wheels. More particularly, the invention relates to a wheeled dolly having a coupler which is capable of connecting rigidly to the end of the cantilevered reach of the long-log trailer so that the dolly and the long-log trailer can be joined to form the short-log trailer.
In the logging industry, cut logs are transported on rigs consisting of a tractor which is coupled to one or more wheeled trailer assemblies. Logs exceeding a certain length are transported on "long-log" rigs, one of which is illustrated in FIG. 1. A long-log rig typically comprises a wheeled trailer having a telescoping cantilevered reach which is connected to a tractor. Raised bunks are placed over the rear wheels of the tractor and the wheels of the trailer for supporting the logs.
Shorter logs are transported on a "short-log" rig such as is illustrated in FIG. 2, comprising a unitary trailer having spaced-apart sets of wheels, which is connected by a tongue to a tractor. Pairs of bunk assemblies are positioned on the bed of the tractor assembly and on the trailer assembly to support two sets of logs.
Presently, a trucker must keep both short-log and long-log trailer assemblies on hand in order to be able to transport both types of logs economically since truck size is regulated with respect to both weight and length. This can result in substantial costs associated with the acquisition, storage and maintenance of log trailers.
Another problem associated with existing short-log trailers is that the distance between the spaced-apart sets of wheels is fixed. Thus they normally are sized to carry the shortest logs which will be transported. As a result, there exist logs which are too long to be carried on a short-log trailer, due to excessive overhang, and yet are short enough that it is not economically efficient to haul them on a long-log trailer, due to the low total load weight. Furthermore, the distance between load-bearing axles is normally controlled by state law, and the requirement can vary from state to state. Thus, a short-log trailer used in interstate commerce must conform to the minimum length allowed along its route of travel, resulting in lost revenue in states where the length allowance exceeds the length of the trailer.
A possible solution to the problems described above would be to provide a set of modular components which can be easily assembled and disassembled to provide the short-log or long-log trailer configurations as needed. One approach that has been tried is to adapt the long-log trailer to attach to a wheeled dolly having a fifth wheel. This would allow making a short-log trailer from a long-log trailer by interconnecting the dolly between a tractor and the long-log trailer. However, this is not a desirable solution because the fifth wheel suspension permits the front end of the short-log trailer to move vertically with respect to the ground which can result in a potentially dangerous shifting of the load of logs.
Accordingly, the problem is to provide a set of modular assemblies which can be assembled to form a short-log trailer which will carry a load of logs in a substantially horizontal position with respect to the ground.